Effect of Expanded Graphite on Mechanical and Tribological Properties of Polyamide 6/Glass Fibre Composites

Abstract

The quality of plastic gears, especially their durability, is becoming increasingly important due to advances in electric mobility. Therefore, new materials are being developed that must have better mechanical properties, high thermal conductivity for heat dissipation, and tribological properties. The composites of expanded graphite (EG) and glass fibre-reinforced polyamide 6 (PA6/GF) were prepared, and the effect of EG particle size (~5 μm (EG5) and ~1000 μm (EG1000)) on these properties was investigated. Composites with different contents (2-10 wt%) of EG in PA6/GF were prepared using a laboratory twin-screw extruder and then injection moulded in the form of rods and discs required for thermal, thermomechanical, and tribological tests. EG acted as a nucleating agent but hindered the crystallization rate at higher concentrations, which was more pronounced when EG5 was added. Dynamic mechanical analysis showed that the storage modulus increased with the addition of both types of EG. However, the addition of EG5 increased the storage modulus more than EG1000. The lowest coefficient of friction was obtained by the addition of 10 wt% EG5. The wear increased with the addition of both types of EG, only slightly with the addition of EG1000. The thermal conductivity of the composites with EG increased from 0.42 W/mK to 1 W/mK. The results show that the use of EG with smaller particle size is much more beneficial than with a larger one.

The Influence of Graphite Filler on the Viscoelastic and Mechanical Characteristics of PC/ABS Hybrid Composite for Automotive Applications

“…It was observed that the storage modulus of the prepared composite with 9 wt% of graphite incorporated PC/ABS blend has the highest modulus over the entire temperature range compared to the other compositions and earlier researchers had similar results [19]. It was reported that the storage modulus of thermoplastic matrices improved with the addition of fillers [23]- [24], [27], [28]. An interesting result was found that the storage modulus decreased correspondingly to 3 wt% of graphite in the PC/ABS blend, but it improved at 6 and 9 wt% of graphite content in the same matrix.…”

Improving the specific wear rate and coefficient of friction of polyamide 6 polymer and its composite by adding wax under self‐operation conditions

“…The degree of crystallinity of graphite and wax filled composites decreases with the addition of graphite and wax filler to the polymer matrix [40]. The degree of crystallinity of the glass fiber reinforced polyamide 6 composites decreases with the increase in the expanded graphite ratio [41].…”

Tribological and Mechanical Applications of Liquid-Crystal-Polymer-Modified Carbon-Fiber-Reinforced Polyamide–Polyurethane Composites

“…For instance, when 10 wt.% Gr was added into the thermoplastic polyurethane (TPU) blend, a reduction in friction was achieved but with an adverse effect on the wear rate, while causing viscosity to increase 2.3 times and strength to decrease by 70% compared to the TPU blend [20]. Multi-component hybrid reinforcements have also been reported for improving tribological properties in polyamide or polyurethane composites [21][22][23]. Vikram et al [21] discovered that incorporating 5% glass fiber with 1% graphite could decrease the coefficient of friction and specific wear rate of the composite while increasing the tensile strength and modulus up to 1.5 times compared to pure PA66.…”